llvm/lib/Target/TargetAsmInfo.cpp - toolchain/llvm-project - Gitiles

 //===-- TargetAsmInfo.cpp - Asm Info ---------------------------------------==//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file defines target asm properties related what form asm statements
 // should take.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Constants.h"
 #include "llvm/DerivedTypes.h"
 #include "llvm/GlobalVariable.h"
 #include "llvm/Function.h"
 #include "llvm/Module.h"
 #include "llvm/Type.h"
 #include "llvm/Target/TargetAsmInfo.h"
 #include "llvm/Target/TargetData.h"
 #include "llvm/Target/TargetMachine.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/ErrorHandling.h"
 #include <cctype>
 #include <cstring>
 using namespace llvm;

 TargetAsmInfo::TargetAsmInfo(const TargetMachine &tm) : TM(tm) {
   BSSSection = "\t.bss";
   BSSSection_ = 0;
   ReadOnlySection = 0;
   TLSDataSection = 0;
   TLSBSSSection = 0;
   ZeroFillDirective = 0;
   NonexecutableStackDirective = 0;
   NeedsSet = false;
   MaxInstLength = 4;
   PCSymbol = "$";
   SeparatorChar = ';';
   CommentColumn = 60;
   CommentString = "#";
   FirstOperandColumn = 0;
   MaxOperandLength = 0;
   GlobalPrefix = "";
   PrivateGlobalPrefix = ".";
   LinkerPrivateGlobalPrefix = "";
   JumpTableSpecialLabelPrefix = 0;
   GlobalVarAddrPrefix = "";
   GlobalVarAddrSuffix = "";
   FunctionAddrPrefix = "";
   FunctionAddrSuffix = "";
   PersonalityPrefix = "";
   PersonalitySuffix = "";
   NeedsIndirectEncoding = false;
   InlineAsmStart = "#APP";
   InlineAsmEnd = "#NO_APP";
   AssemblerDialect = 0;
   AllowQuotesInName = false;
   ZeroDirective = "\t.zero\t";
   ZeroDirectiveSuffix = 0;
   AsciiDirective = "\t.ascii\t";
   AscizDirective = "\t.asciz\t";
   Data8bitsDirective = "\t.byte\t";
   Data16bitsDirective = "\t.short\t";
   Data32bitsDirective = "\t.long\t";
   Data64bitsDirective = "\t.quad\t";
   AlignDirective = "\t.align\t";
   AlignmentIsInBytes = true;
   TextAlignFillValue = 0;
   SwitchToSectionDirective = "\t.section\t";
   TextSectionStartSuffix = "";
   DataSectionStartSuffix = "";
   SectionEndDirectiveSuffix = 0;
   ConstantPoolSection = "\t.section .rodata";
   JumpTableDataSection = "\t.section .rodata";
   JumpTableDirective = 0;
   CStringSection = 0;
   CStringSection_ = 0;
   // FIXME: Flags are ELFish - replace with normal section stuff.
   StaticCtorsSection = "\t.section .ctors,\"aw\",@progbits";
   StaticDtorsSection = "\t.section .dtors,\"aw\",@progbits";
   GlobalDirective = "\t.globl\t";
   SetDirective = 0;
   LCOMMDirective = 0;
   COMMDirective = "\t.comm\t";
   COMMDirectiveTakesAlignment = true;
   HasDotTypeDotSizeDirective = true;
   HasSingleParameterDotFile = true;
   UsedDirective = 0;
   WeakRefDirective = 0;
   WeakDefDirective = 0;
   // FIXME: These are ELFish - move to ELFTAI.
   HiddenDirective = "\t.hidden\t";
   ProtectedDirective = "\t.protected\t";
   AbsoluteDebugSectionOffsets = false;
   AbsoluteEHSectionOffsets = false;
   HasLEB128 = false;
   HasDotLocAndDotFile = false;
   SupportsDebugInformation = false;
   SupportsExceptionHandling = false;
   DwarfRequiresFrameSection = true;
   DwarfUsesInlineInfoSection = false;
   Is_EHSymbolPrivate = true;
   GlobalEHDirective = 0;
   SupportsWeakOmittedEHFrame = true;
   DwarfSectionOffsetDirective = 0;
   DwarfAbbrevSection = ".debug_abbrev";
   DwarfInfoSection = ".debug_info";
   DwarfLineSection = ".debug_line";
   DwarfFrameSection = ".debug_frame";
   DwarfPubNamesSection = ".debug_pubnames";
   DwarfPubTypesSection = ".debug_pubtypes";
   DwarfDebugInlineSection = ".debug_inlined";
   DwarfStrSection = ".debug_str";
   DwarfLocSection = ".debug_loc";
   DwarfARangesSection = ".debug_aranges";
   DwarfRangesSection = ".debug_ranges";
   DwarfMacroInfoSection = ".debug_macinfo";
   DwarfEHFrameSection = ".eh_frame";
   DwarfExceptionSection = ".gcc_except_table";
   AsmTransCBE = 0;
   TextSection = getUnnamedSection("\t.text", SectionFlags::Code);
   DataSection = getUnnamedSection("\t.data", SectionFlags::Writable);
 }

 TargetAsmInfo::~TargetAsmInfo() {
 }

 /// Measure the specified inline asm to determine an approximation of its
 /// length.
 /// Comments (which run till the next SeparatorChar or newline) do not
 /// count as an instruction.
 /// Any other non-whitespace text is considered an instruction, with
 /// multiple instructions separated by SeparatorChar or newlines.
 /// Variable-length instructions are not handled here; this function
 /// may be overloaded in the target code to do that.
 unsigned TargetAsmInfo::getInlineAsmLength(const char *Str) const {
   // Count the number of instructions in the asm.
   bool atInsnStart = true;
   unsigned Length = 0;
   for (; *Str; ++Str) {
     if (*Str == '\n' || *Str == SeparatorChar)
       atInsnStart = true;
     if (atInsnStart && !isspace(*Str)) {
       Length += MaxInstLength;
       atInsnStart = false;
     }
     if (atInsnStart && strncmp(Str, CommentString, strlen(CommentString))==0)
       atInsnStart = false;
   }

   return Length;
 }

 unsigned TargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
                                               bool Global) const {
   return dwarf::DW_EH_PE_absptr;
 }

 static bool isSuitableForBSS(const GlobalVariable *GV) {
   Constant *C = GV->getInitializer();

   // Must have zero initializer.
   if (!C->isNullValue())
     return false;

   // Leave constant zeros in readonly constant sections, so they can be shared.
   if (GV->isConstant())
     return false;

   // If the global has an explicit section specified, don't put it in BSS.
   if (!GV->getSection().empty())
     return false;

   // If -nozero-initialized-in-bss is specified, don't ever use BSS.
   if (NoZerosInBSS)
     return false;

   // Otherwise, put it in BSS!
   return true;
 }

 static bool isConstantString(const Constant *C) {
   // First check: is we have constant array of i8 terminated with zero
   const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
   // Check, if initializer is a null-terminated string
   if (CVA && CVA->isCString())
     return true;

   // Another possibility: [1 x i8] zeroinitializer
   if (isa<ConstantAggregateZero>(C))
     if (const ArrayType *Ty = dyn_cast<ArrayType>(C->getType()))
       return (Ty->getElementType() == Type::Int8Ty &&
               Ty->getNumElements() == 1);

   return false;
 }

 static unsigned SectionFlagsForGlobal(SectionKind Kind) {
   // Decode flags from global and section kind.
   unsigned Flags = SectionFlags::None;
   if (Kind.isWeak())
     Flags |= SectionFlags::Linkonce;
   if (Kind.isBSS() || Kind.isThreadBSS())
     Flags |= SectionFlags::BSS;
   if (Kind.isThreadLocal())
     Flags |= SectionFlags::TLS;
   if (Kind.isText())
     Flags |= SectionFlags::Code;
   if (Kind.isWriteable())
     Flags |= SectionFlags::Writable;

   return Flags;
 }

 static SectionKind::Kind SectionKindForGlobal(const GlobalValue *GV,
                                               const TargetMachine &TM) {
   Reloc::Model ReloModel = TM.getRelocationModel();

   // Early exit - functions should be always in text sections.
   const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
   if (GVar == 0)
     return SectionKind::Text;


   // Handle thread-local data first.
   if (GVar->isThreadLocal()) {
     if (isSuitableForBSS(GVar))
       return SectionKind::ThreadBSS;
     return SectionKind::ThreadData;
   }

   // Variable can be easily put to BSS section.
   if (isSuitableForBSS(GVar))
     return SectionKind::BSS;

   Constant *C = GVar->getInitializer();

   // If the global is marked constant, we can put it into a mergable section,
   // a mergable string section, or general .data if it contains relocations.
   if (GVar->isConstant()) {
     // If the initializer for the global contains something that requires a
     // relocation, then we may have to drop this into a wriable data section
     // even though it is marked const.
     switch (C->getRelocationInfo()) {
     default: llvm_unreachable("unknown relocation info kind");
     case Constant::NoRelocation:
       // If initializer is a null-terminated string, put it in a "cstring"
       // section if the target has it.
       if (isConstantString(C))
         return SectionKind::MergeableCString;

       // Otherwise, just drop it into a mergable constant section.  If we have
       // a section for this size, use it, otherwise use the arbitrary sized
       // mergable section.
       switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
       case 4:  return SectionKind::MergeableConst4;
       case 8:  return SectionKind::MergeableConst8;
       case 16: return SectionKind::MergeableConst16;
       default: return SectionKind::MergeableConst;
       }

     case Constant::LocalRelocation:
       // In static relocation model, the linker will resolve all addresses, so
       // the relocation entries will actually be constants by the time the app
       // starts up.
       if (ReloModel == Reloc::Static)
         return SectionKind::ReadOnly;

       // Otherwise, the dynamic linker needs to fix it up, put it in the
       // writable data.rel.local section.
       return SectionKind::ReadOnlyWithRelLocal;

     case Constant::GlobalRelocations:
       // In static relocation model, the linker will resolve all addresses, so
       // the relocation entries will actually be constants by the time the app
       // starts up.
       if (ReloModel == Reloc::Static)
         return SectionKind::ReadOnly;

       // Otherwise, the dynamic linker needs to fix it up, put it in the
       // writable data.rel section.
       return SectionKind::ReadOnlyWithRel;
     }
   }

   // Okay, this isn't a constant.  If the initializer for the global is going
   // to require a runtime relocation by the dynamic linker, put it into a more
   // specific section to improve startup time of the app.  This coalesces these
   // globals together onto fewer pages, improving the locality of the dynamic
   // linker.
   if (ReloModel == Reloc::Static)
     return SectionKind::DataNoRel;

   switch (C->getRelocationInfo()) {
   default: llvm_unreachable("unknown relocation info kind");
   case Constant::NoRelocation:
     return SectionKind::DataNoRel;
   case Constant::LocalRelocation:
     return SectionKind::DataRelLocal;
   case Constant::GlobalRelocations:
     return SectionKind::DataRel;
   }
 }

 /// SectionForGlobal - This method computes the appropriate section to emit
 /// the specified global variable or function definition.  This should not
 /// be passed external (or available externally) globals.
 const Section *TargetAsmInfo::SectionForGlobal(const GlobalValue *GV) const {
   assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
          "Can only be used for global definitions");

   SectionKind::Kind GVKind = SectionKindForGlobal(GV, TM);

   SectionKind Kind = SectionKind::get(GVKind, GV->isWeakForLinker(),
                                       GV->hasSection());


   // Select section name.
   if (GV->hasSection()) {
     // If the target has special section hacks for specifically named globals,
     // return them now.
     if (const Section *TS = getSpecialCasedSectionGlobals(GV, Kind))
       return TS;

     // Honour section already set, if any.
     unsigned Flags = SectionFlagsForGlobal(Kind);

     // This is an explicitly named section.
     Flags |= SectionFlags::Named;

     // If the target has magic semantics for certain section names, make sure to
     // pick up the flags.  This allows the user to write things with attribute
     // section and still get the appropriate section flags printed.
     Flags |= getFlagsForNamedSection(GV->getSection().c_str());

     return getNamedSection(GV->getSection().c_str(), Flags);
   }

   // If this global is linkonce/weak and the target handles this by emitting it
   // into a 'uniqued' section name, create and return the section now.
   if (Kind.isWeak()) {
     if (const char *Prefix = getSectionPrefixForUniqueGlobal(Kind)) {
       unsigned Flags = SectionFlagsForGlobal(Kind);

       // FIXME: Use mangler interface (PR4584).
       std::string Name = Prefix+GV->getNameStr();
       return getNamedSection(Name.c_str(), Flags);
     }
   }

   // Use default section depending on the 'type' of global
   return SelectSectionForGlobal(GV, Kind);
 }

 // Lame default implementation. Calculate the section name for global.
 const Section*
 TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
                                       SectionKind Kind) const {
   assert(!Kind.isThreadLocal() && "Doesn't support TLS");

   if (Kind.isText())
     return getTextSection();

   if (Kind.isBSS())
     if (const Section *S = getBSSSection_())
       return S;

   if (Kind.isReadOnly())
     if (const Section *S = getReadOnlySection())
       return S;

   return getDataSection();
 }

 /// getSectionForMergableConstant - Given a mergable constant with the
 /// specified size and relocation information, return a section that it
 /// should be placed in.
 const Section *
 TargetAsmInfo::getSectionForMergeableConstant(SectionKind Kind) const {
   if (Kind.isReadOnly())
     if (const Section *S = getReadOnlySection())
       return S;

   return getDataSection();
 }


 const Section *TargetAsmInfo::getNamedSection(const char *Name, unsigned Flags,
                                               bool Override) const {
   Section &S = Sections[Name];

   // This is newly-created section, set it up properly.
   if (S.Flags == SectionFlags::Invalid || Override) {
     S.Flags = Flags | SectionFlags::Named;
     S.Name = Name;
   }

   return &S;
 }

 const Section*
 TargetAsmInfo::getUnnamedSection(const char *Directive, unsigned Flags,
                                  bool Override) const {
   Section& S = Sections[Directive];

   // This is newly-created section, set it up properly.
   if (S.Flags == SectionFlags::Invalid || Override) {
     S.Flags = Flags & ~SectionFlags::Named;
     S.Name = Directive;
   }

   return &S;
 }

 const std::string&
 TargetAsmInfo::getSectionFlags(unsigned Flags) const {
   SectionFlags::FlagsStringsMapType::iterator I = FlagsStrings.find(Flags);

   // We didn't print these flags yet, print and save them to map. This reduces
   // amount of heap trashing due to std::string construction / concatenation.
   if (I == FlagsStrings.end())
     I = FlagsStrings.insert(std::make_pair(Flags,
                                            printSectionFlags(Flags))).first;

   return I->second;
 }

 unsigned TargetAsmInfo::getULEB128Size(unsigned Value) {
   unsigned Size = 0;
   do {
     Value >>= 7;
     Size += sizeof(int8_t);
   } while (Value);
   return Size;
 }

 unsigned TargetAsmInfo::getSLEB128Size(int Value) {
   unsigned Size = 0;
   int Sign = Value >> (8 * sizeof(Value) - 1);
   bool IsMore;

   do {
     unsigned Byte = Value & 0x7f;
     Value >>= 7;
     IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
     Size += sizeof(int8_t);
   } while (IsMore);
   return Size;
 }
	//===-- TargetAsmInfo.cpp - Asm Info ---------------------------------------==//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file defines target asm properties related what form asm statements
	// should take.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Constants.h"
	#include "llvm/DerivedTypes.h"
	#include "llvm/GlobalVariable.h"
	#include "llvm/Function.h"
	#include "llvm/Module.h"
	#include "llvm/Type.h"
	#include "llvm/Target/TargetAsmInfo.h"
	#include "llvm/Target/TargetData.h"
	#include "llvm/Target/TargetMachine.h"
	#include "llvm/Target/TargetOptions.h"
	#include "llvm/Support/Dwarf.h"
	#include "llvm/Support/ErrorHandling.h"
	#include <cctype>
	#include <cstring>
	using namespace llvm;

	TargetAsmInfo::TargetAsmInfo(const TargetMachine &tm) : TM(tm) {
	BSSSection = "\t.bss";
	BSSSection_ = 0;
	ReadOnlySection = 0;
	TLSDataSection = 0;
	TLSBSSSection = 0;
	ZeroFillDirective = 0;
	NonexecutableStackDirective = 0;
	NeedsSet = false;
	MaxInstLength = 4;
	PCSymbol = "$";
	SeparatorChar = ';';
	CommentColumn = 60;
	CommentString = "#";
	FirstOperandColumn = 0;
	MaxOperandLength = 0;
	GlobalPrefix = "";
	PrivateGlobalPrefix = ".";
	LinkerPrivateGlobalPrefix = "";
	JumpTableSpecialLabelPrefix = 0;
	GlobalVarAddrPrefix = "";
	GlobalVarAddrSuffix = "";
	FunctionAddrPrefix = "";
	FunctionAddrSuffix = "";
	PersonalityPrefix = "";
	PersonalitySuffix = "";
	NeedsIndirectEncoding = false;
	InlineAsmStart = "#APP";
	InlineAsmEnd = "#NO_APP";
	AssemblerDialect = 0;
	AllowQuotesInName = false;
	ZeroDirective = "\t.zero\t";
	ZeroDirectiveSuffix = 0;
	AsciiDirective = "\t.ascii\t";
	AscizDirective = "\t.asciz\t";
	Data8bitsDirective = "\t.byte\t";
	Data16bitsDirective = "\t.short\t";
	Data32bitsDirective = "\t.long\t";
	Data64bitsDirective = "\t.quad\t";
	AlignDirective = "\t.align\t";
	AlignmentIsInBytes = true;
	TextAlignFillValue = 0;
	SwitchToSectionDirective = "\t.section\t";
	TextSectionStartSuffix = "";
	DataSectionStartSuffix = "";
	SectionEndDirectiveSuffix = 0;
	ConstantPoolSection = "\t.section .rodata";
	JumpTableDataSection = "\t.section .rodata";
	JumpTableDirective = 0;
	CStringSection = 0;
	CStringSection_ = 0;
	// FIXME: Flags are ELFish - replace with normal section stuff.
	StaticCtorsSection = "\t.section .ctors,\"aw\",@progbits";
	StaticDtorsSection = "\t.section .dtors,\"aw\",@progbits";
	GlobalDirective = "\t.globl\t";
	SetDirective = 0;
	LCOMMDirective = 0;
	COMMDirective = "\t.comm\t";
	COMMDirectiveTakesAlignment = true;
	HasDotTypeDotSizeDirective = true;
	HasSingleParameterDotFile = true;
	UsedDirective = 0;
	WeakRefDirective = 0;
	WeakDefDirective = 0;
	// FIXME: These are ELFish - move to ELFTAI.
	HiddenDirective = "\t.hidden\t";
	ProtectedDirective = "\t.protected\t";
	AbsoluteDebugSectionOffsets = false;
	AbsoluteEHSectionOffsets = false;
	HasLEB128 = false;
	HasDotLocAndDotFile = false;
	SupportsDebugInformation = false;
	SupportsExceptionHandling = false;
	DwarfRequiresFrameSection = true;
	DwarfUsesInlineInfoSection = false;
	Is_EHSymbolPrivate = true;
	GlobalEHDirective = 0;
	SupportsWeakOmittedEHFrame = true;
	DwarfSectionOffsetDirective = 0;
	DwarfAbbrevSection = ".debug_abbrev";
	DwarfInfoSection = ".debug_info";
	DwarfLineSection = ".debug_line";
	DwarfFrameSection = ".debug_frame";
	DwarfPubNamesSection = ".debug_pubnames";
	DwarfPubTypesSection = ".debug_pubtypes";
	DwarfDebugInlineSection = ".debug_inlined";
	DwarfStrSection = ".debug_str";
	DwarfLocSection = ".debug_loc";
	DwarfARangesSection = ".debug_aranges";
	DwarfRangesSection = ".debug_ranges";
	DwarfMacroInfoSection = ".debug_macinfo";
	DwarfEHFrameSection = ".eh_frame";
	DwarfExceptionSection = ".gcc_except_table";
	AsmTransCBE = 0;
	TextSection = getUnnamedSection("\t.text", SectionFlags::Code);
	DataSection = getUnnamedSection("\t.data", SectionFlags::Writable);
	}

	TargetAsmInfo::~TargetAsmInfo() {
	}

	/// Measure the specified inline asm to determine an approximation of its
	/// length.
	/// Comments (which run till the next SeparatorChar or newline) do not
	/// count as an instruction.
	/// Any other non-whitespace text is considered an instruction, with
	/// multiple instructions separated by SeparatorChar or newlines.
	/// Variable-length instructions are not handled here; this function
	/// may be overloaded in the target code to do that.
	unsigned TargetAsmInfo::getInlineAsmLength(const char *Str) const {
	// Count the number of instructions in the asm.
	bool atInsnStart = true;
	unsigned Length = 0;
	for (; *Str; ++Str) {
	if (Str == '\n' \|\| Str == SeparatorChar)
	atInsnStart = true;
	if (atInsnStart && !isspace(*Str)) {
	Length += MaxInstLength;
	atInsnStart = false;
	}
	if (atInsnStart && strncmp(Str, CommentString, strlen(CommentString))==0)
	atInsnStart = false;
	}

	return Length;
	}

	unsigned TargetAsmInfo::PreferredEHDataFormat(DwarfEncoding::Target Reason,
	bool Global) const {
	return dwarf::DW_EH_PE_absptr;
	}

	static bool isSuitableForBSS(const GlobalVariable *GV) {
	Constant *C = GV->getInitializer();

	// Must have zero initializer.
	if (!C->isNullValue())
	return false;

	// Leave constant zeros in readonly constant sections, so they can be shared.
	if (GV->isConstant())
	return false;

	// If the global has an explicit section specified, don't put it in BSS.
	if (!GV->getSection().empty())
	return false;

	// If -nozero-initialized-in-bss is specified, don't ever use BSS.
	if (NoZerosInBSS)
	return false;

	// Otherwise, put it in BSS!
	return true;
	}

	static bool isConstantString(const Constant *C) {
	// First check: is we have constant array of i8 terminated with zero
	const ConstantArray *CVA = dyn_cast<ConstantArray>(C);
	// Check, if initializer is a null-terminated string
	if (CVA && CVA->isCString())
	return true;

	// Another possibility: [1 x i8] zeroinitializer
	if (isa<ConstantAggregateZero>(C))
	if (const ArrayType *Ty = dyn_cast<ArrayType>(C->getType()))
	return (Ty->getElementType() == Type::Int8Ty &&
	Ty->getNumElements() == 1);

	return false;
	}

	static unsigned SectionFlagsForGlobal(SectionKind Kind) {
	// Decode flags from global and section kind.
	unsigned Flags = SectionFlags::None;
	if (Kind.isWeak())
	Flags \|= SectionFlags::Linkonce;
	if (Kind.isBSS() \|\| Kind.isThreadBSS())
	Flags \|= SectionFlags::BSS;
	if (Kind.isThreadLocal())
	Flags \|= SectionFlags::TLS;
	if (Kind.isText())
	Flags \|= SectionFlags::Code;
	if (Kind.isWriteable())
	Flags \|= SectionFlags::Writable;

	return Flags;
	}

	static SectionKind::Kind SectionKindForGlobal(const GlobalValue *GV,
	const TargetMachine &TM) {
	Reloc::Model ReloModel = TM.getRelocationModel();

	// Early exit - functions should be always in text sections.
	const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV);
	if (GVar == 0)
	return SectionKind::Text;


	// Handle thread-local data first.
	if (GVar->isThreadLocal()) {
	if (isSuitableForBSS(GVar))
	return SectionKind::ThreadBSS;
	return SectionKind::ThreadData;
	}

	// Variable can be easily put to BSS section.
	if (isSuitableForBSS(GVar))
	return SectionKind::BSS;

	Constant *C = GVar->getInitializer();

	// If the global is marked constant, we can put it into a mergable section,
	// a mergable string section, or general .data if it contains relocations.
	if (GVar->isConstant()) {
	// If the initializer for the global contains something that requires a
	// relocation, then we may have to drop this into a wriable data section
	// even though it is marked const.
	switch (C->getRelocationInfo()) {
	default: llvm_unreachable("unknown relocation info kind");
	case Constant::NoRelocation:
	// If initializer is a null-terminated string, put it in a "cstring"
	// section if the target has it.
	if (isConstantString(C))
	return SectionKind::MergeableCString;

	// Otherwise, just drop it into a mergable constant section. If we have
	// a section for this size, use it, otherwise use the arbitrary sized
	// mergable section.
	switch (TM.getTargetData()->getTypeAllocSize(C->getType())) {
	case 4: return SectionKind::MergeableConst4;
	case 8: return SectionKind::MergeableConst8;
	case 16: return SectionKind::MergeableConst16;
	default: return SectionKind::MergeableConst;
	}

	case Constant::LocalRelocation:
	// In static relocation model, the linker will resolve all addresses, so
	// the relocation entries will actually be constants by the time the app
	// starts up.
	if (ReloModel == Reloc::Static)
	return SectionKind::ReadOnly;

	// Otherwise, the dynamic linker needs to fix it up, put it in the
	// writable data.rel.local section.
	return SectionKind::ReadOnlyWithRelLocal;

	case Constant::GlobalRelocations:
	// In static relocation model, the linker will resolve all addresses, so
	// the relocation entries will actually be constants by the time the app
	// starts up.
	if (ReloModel == Reloc::Static)
	return SectionKind::ReadOnly;

	// Otherwise, the dynamic linker needs to fix it up, put it in the
	// writable data.rel section.
	return SectionKind::ReadOnlyWithRel;
	}
	}

	// Okay, this isn't a constant. If the initializer for the global is going
	// to require a runtime relocation by the dynamic linker, put it into a more
	// specific section to improve startup time of the app. This coalesces these
	// globals together onto fewer pages, improving the locality of the dynamic
	// linker.
	if (ReloModel == Reloc::Static)
	return SectionKind::DataNoRel;

	switch (C->getRelocationInfo()) {
	default: llvm_unreachable("unknown relocation info kind");
	case Constant::NoRelocation:
	return SectionKind::DataNoRel;
	case Constant::LocalRelocation:
	return SectionKind::DataRelLocal;
	case Constant::GlobalRelocations:
	return SectionKind::DataRel;
	}
	}

	/// SectionForGlobal - This method computes the appropriate section to emit
	/// the specified global variable or function definition. This should not
	/// be passed external (or available externally) globals.
	const Section TargetAsmInfo::SectionForGlobal(const GlobalValue GV) const {
	assert(!GV->isDeclaration() && !GV->hasAvailableExternallyLinkage() &&
	"Can only be used for global definitions");

	SectionKind::Kind GVKind = SectionKindForGlobal(GV, TM);

	SectionKind Kind = SectionKind::get(GVKind, GV->isWeakForLinker(),
	GV->hasSection());


	// Select section name.
	if (GV->hasSection()) {
	// If the target has special section hacks for specifically named globals,
	// return them now.
	if (const Section *TS = getSpecialCasedSectionGlobals(GV, Kind))
	return TS;

	// Honour section already set, if any.
	unsigned Flags = SectionFlagsForGlobal(Kind);

	// This is an explicitly named section.
	Flags \|= SectionFlags::Named;

	// If the target has magic semantics for certain section names, make sure to
	// pick up the flags. This allows the user to write things with attribute
	// section and still get the appropriate section flags printed.
	Flags \|= getFlagsForNamedSection(GV->getSection().c_str());

	return getNamedSection(GV->getSection().c_str(), Flags);
	}

	// If this global is linkonce/weak and the target handles this by emitting it
	// into a 'uniqued' section name, create and return the section now.
	if (Kind.isWeak()) {
	if (const char *Prefix = getSectionPrefixForUniqueGlobal(Kind)) {
	unsigned Flags = SectionFlagsForGlobal(Kind);

	// FIXME: Use mangler interface (PR4584).
	std::string Name = Prefix+GV->getNameStr();
	return getNamedSection(Name.c_str(), Flags);
	}
	}

	// Use default section depending on the 'type' of global
	return SelectSectionForGlobal(GV, Kind);
	}

	// Lame default implementation. Calculate the section name for global.
	const Section*
	TargetAsmInfo::SelectSectionForGlobal(const GlobalValue *GV,
	SectionKind Kind) const {
	assert(!Kind.isThreadLocal() && "Doesn't support TLS");

	if (Kind.isText())
	return getTextSection();

	if (Kind.isBSS())
	if (const Section *S = getBSSSection_())
	return S;

	if (Kind.isReadOnly())
	if (const Section *S = getReadOnlySection())
	return S;

	return getDataSection();
	}

	/// getSectionForMergableConstant - Given a mergable constant with the
	/// specified size and relocation information, return a section that it
	/// should be placed in.
	const Section *
	TargetAsmInfo::getSectionForMergeableConstant(SectionKind Kind) const {
	if (Kind.isReadOnly())
	if (const Section *S = getReadOnlySection())
	return S;

	return getDataSection();
	}


	const Section TargetAsmInfo::getNamedSection(const char Name, unsigned Flags,
	bool Override) const {
	Section &S = Sections[Name];

	// This is newly-created section, set it up properly.
	if (S.Flags == SectionFlags::Invalid \|\| Override) {
	S.Flags = Flags \| SectionFlags::Named;
	S.Name = Name;
	}

	return &S;
	}

	const Section*
	TargetAsmInfo::getUnnamedSection(const char *Directive, unsigned Flags,
	bool Override) const {
	Section& S = Sections[Directive];

	// This is newly-created section, set it up properly.
	if (S.Flags == SectionFlags::Invalid \|\| Override) {
	S.Flags = Flags & ~SectionFlags::Named;
	S.Name = Directive;
	}

	return &S;
	}

	const std::string&
	TargetAsmInfo::getSectionFlags(unsigned Flags) const {
	SectionFlags::FlagsStringsMapType::iterator I = FlagsStrings.find(Flags);

	// We didn't print these flags yet, print and save them to map. This reduces
	// amount of heap trashing due to std::string construction / concatenation.
	if (I == FlagsStrings.end())
	I = FlagsStrings.insert(std::make_pair(Flags,
	printSectionFlags(Flags))).first;

	return I->second;
	}

	unsigned TargetAsmInfo::getULEB128Size(unsigned Value) {
	unsigned Size = 0;
	do {
	Value >>= 7;
	Size += sizeof(int8_t);
	} while (Value);
	return Size;
	}

	unsigned TargetAsmInfo::getSLEB128Size(int Value) {
	unsigned Size = 0;
	int Sign = Value >> (8 * sizeof(Value) - 1);
	bool IsMore;

	do {
	unsigned Byte = Value & 0x7f;
	Value >>= 7;
	IsMore = Value != Sign \|\| ((Byte ^ Sign) & 0x40) != 0;
	Size += sizeof(int8_t);
	} while (IsMore);
	return Size;
	}